S(H)DSL at a Glance 10 Mb/s Single Twisted Pair Ethernet Study Group Nov 2016, Mario Traeber
Connected Home Division Introduction
This presentation introduces SHDSL as a technology to support the CSD for 10SPE. The focus is mostly on feasibility of a Twisted Pair PHY ranging to 1km at 10Mbps full-duplex data transmission. An introduction to the standards history, technology features and properties as well as performance characteristics will be presented. The presentation concludes with a discussion on what would need to be explored further to apply the underlying technology principles to the objectives of 10SPE.
Connected Home Division Standards Overview The history of SHDSL in various standards bodies and it’s relation into IEEE SDSL and SHDSL Standardization
ISDN Relationship Ÿ synchronous Ÿ 2B1Q Ÿ 144 kbit/s HDSL between ISDN, Ÿ plesiochronous Ÿ 2B1Q HDSL, HDSL2, Ÿ 2320 kbit/s (1 line) MDSL Ÿ plesiochronous MDSL, SDSL and MDSL (MuBIC) Ÿ 2B1Q Ÿ 272, 400, 528, Ÿ synchronous 784 kbit/s Ÿ TC-PAM SHDSL Ÿ Multi bitrate 160 - 1040 ANSI- kbit/s SDSL Ÿ plesiochronous HDSL2 Ÿ 2B1Q Ÿ plesiochronous ETSI- Ÿ Multi bitrate Ÿ TC-PAM Standards SDSL Ÿ 1544 kbit/s ISDN (ETSI 1988) Ÿ synchronous + plesiochronous HDSL (ETSI 1996) Ÿ TC-PAM Ÿ Multi bitrate 200 - HDSL2 (ANSI 1999) 2320 kbit/s SDSL (ETSI, 2000) SHDSL (ITU, 2000) SHDSL Ÿ synchronous + plesiochronous Ÿ TC-PAM Ÿ Multi bitrate 200 - 2320 kbit/s
Connected Home Division SDSL and SHDSL Standardization (2)
Major ETSI Decisions on SDSL Major ITU-T Decisions on SHDSL • Line code • Line code • PSDs • PSDs (North America) • Network synchronization • Network synchronization • Data rates • Data rates (North America) • Frame structure • Frame structure • EOC • EOC • Electrical characteristics • Electrical characteristics • Activation • Activation • Pre-activation • Pre-activation • ISDN transport • Test loops • Test loops (North America) • Noise models • Noise models (North America) • ATM annex
Connected Home Division 5 SDSL and SHDSL Standardization
SDSL Data Rates • Multi bit rate system • Payload bit rates 192 kbit/s - 2312 kbit/s • 8 kbit/s granularity SHDSL Data Rates • Multi bit rate system • Payload bit rates 192 kbit/s - 2304 kbit/s • North America: N• 64 kbit/s or N• 64 kbit/s + 8 kbit/s (payload)
Connected Home Division SDSL and SHDSL Standardization
Start Up Procedure . Activation: – Basic structure of HDSL2 activation sequence . Preactivation: – g.hs Management . Clear eoc channel . HDSL2 channel proocol
Connected Home Division ITU-T G.991.2 Annex F&G (SHDSL.bis) Higher data rates
TC-PAM Levels Standard Part of Data rates (Bits / Symbol: B-Channels Symbol Rates G.992.1 [kbps] Payload+OH) Z-Bits [kbaud]
Annex A+B 3B + 0Z 66,7 (Standard SHDSL) 192..2312 16 (3+1) ...... 36B + 1Z 773,3
3B + 0Z 66,7 192..3840 16 (3+1) ...... 60B + 0Z 1282,7 Annex F+G (SHDSL.bis) 12B + 0Z 194 768...5696 32 (4+1) ...... 89B + 0Z 1426
Connected Home Division ITU-T G.991.2 Annex F&G (SHDSL.bis) Enhanced G.994.1 (G.hs) startup
G.992.1 SHDSL (old) Caplist Version 1 Standard -Bit mask for Baserates and Subrates -Enabling each single baserate and subrate -Bit mask applied to TCPAM-16 only
Extension for Annex F+G Caplist Version 2: contains additionally -Ranges of Baserates per coding -3-tuple per coding TCPAM-16 and TCPAM-32 (min, max, step) Example: (40,70,10) means: 40x64kbps, 50x64kbps, 60x64kbps, 70x64kbps -Overlap of ranges is possible
Connected Home Division ITU-T G.991.2 (SHDSL.bis) Multi-Channel bonding (M-Pair)
Standard Part of Line Bonding Level Interleaving Interleaving G.992.1 Bonding Order of Subchannels Annex A+B Byte (Standard SHDSL) 4-wire OSI-Layer 1 Interleaving Master / Slave
add-ons in Interleaving acc. Annex F+G M-Pair OSI-Layer 1 Byte to negotiatioin in (SHDSL.bis) (M=1,2..4) Interleaving Activation Frame
Connected Home Division 11 xDSL rate/reach performance compared
Data rate [Mbit/s]
200/100 VDSL
Extended PAM levels 15 Mbps per channel 100/50 Extended reach
24/2 Standard compliant mode 5 Mbps per channel ADSL 15/15 Extended 4..128 PAM levels 5/5 G.SHDSL 16/32 PAM levels
0.1 km 1 km 3 km 5 km Reach
Connected Home Division New and edited chapters ETHoverDSL @ IEEE 802.3ah (SHDSL relevant) • Clause 30 (EFM=Ethernet First Mile) • Clause 45 • Clause 57 MAC control (optional) • Clause 61 • Clause 63 MAC Standard Ethernet MII (optional) MAC PHY Rate Matching PHY PMI Aggregation Adaptation functions TPS-TC (64B/65B) PMA (PMS-TC) xDSL specific PMD
Connected Home Division MAC PHY Rate matching Rate Matching
Adapts the MAC/MII bit-rate (100Mbps) to the lower (aggregate) PHY bit-rate(s) MAC is operated in half-duplex mode . Note: It should still be able to transmit and receive simultaneously CRS function is used by the PHY to prevent MAC from sending another MAC frame Preamble and SFD are removed PHY needs to buffer one maximum length frame (i.e. 1522 Bytes) in both directions
Connected Home Division PHY PMI Aggregation Function (PAF) PAF
Connected Home Division PHY PMI Aggregation Function (PAF) PAF Provides a flexible mapping of a MAC to different PHYs Purpose is to increase the bandwidth and to provide redundancy PAF will be negotiated using g.994.1 ( 2 Phases) *) Implementation is PHY specific – Combination of 10PASS-TS and 2BASE-TL theoretically possible Restrictions – Speed ratio between fastest and slowest link must be < 4 – Differential delay <15000 bit times – Frame size between 64 and 512 Bytes with a 4 Byte granularity – Up to 32 PHYs per MAC Transmit sequence can be vendor specific *) we’ll have a dedicated session on EFM handshake and PAF
Connected Home Division Encapsulation (64B/65B) TPS-TC
Input is either a MAC frame or a PMI aggregation fragment A 32bit(SHDSL)/16bit (VDSL) FCS will be calculated and added at the end of each frame/fragment (“TC-frame”) This TC-frame is chopped into 64-Bytes packets One Sync-Byte is added at the beginning to indicate the content of the following 64-Bytes packet resulting in a 65-Bytes “Codeword”
. Sync-Byte 0F16 indicates that all 64 following bytes are data from the very same data frame
. Sync-Byte F016 requires a look at the first payload bit D1 – If Zero, wait for a frame start Byte – If not Zero it contains the position of the last Byte of the frame
Connected Home Division IEEE EFM Physical layers for copper lines PMD
10PASS-TS . 10 Mbps, PASSband, Twisted Pair, Short Reach . Using VDSL2 technology . Based on ANSI T1.424/trial use standard 2BASE-TL . 2Mbps, BASE-band, Twisted Pair, Long Reach . Based on SHDSL technology . Using ITU-T G.991.2.bis standard . Allowing 32-PAM coding for higher bit-rates
Connected Home Division 10PASS-TS Objectives PMD
• To provide 100 Mb/s data rate at the MII. • To provide ~10Mb/s encapsulated packet data rate at the α(β) interface. • To provide full duplex operation. • To provide for operating over non-loaded voice grade twisted pair cable at distances up to 750 m (2.5 kfeet). • To provide a communication channel with a mean bit error rate, at the α(β) interface, of less than one part in 107 with 6 dB noise margin. • To provide optional support for operation on multiple pairs • All band-plans are allowed • To have only one line code Connected Home Division 2BASE-TL Objectives PMD
• To provide 100 Mb/s data rate at the MII. • To provide ~2Mb/s encapsulated packet data rate at the α(β) interface. • To provide full duplex operation. • To provide for operating over non-loaded voice grade twisted pair cable at distances up to 2,700 m (9 kfeet). • To provide a communication channel with a mean bit error rate, at the α(β) interface, of less than one part in 107 with 5 dB noise margin. • To provide optional support for operation on multiple pairs • All data rates from 192 kbps up to 5696 kbps in a 64kbps granularity are supported • Focus is on 512, 704, 1024, 2048, 3072 and 5696 kbps Connected Home Division *) Bonding on OSI-Layer 1, Byte interleaving **) Bonding on OSI-Layer 2, Payload Interleaving Standards Summary
Comparison of Symmetrical Data Technologies
SDSL SHDSL SHDSL.bis EFM 2Base-TL
192kbps - 2.3Mbps 192..5696 kbps Data Rate 192kbps - 2.3Mbps or per pair 384kbps – 4.624Mbps
Pairs 1 1 or 2 *) 1-4 *) 1..32 **) Line Code 2B1Q TC PAM 16 TC PAM 16/32 TC PAM 16 / 32 EOC Proprietary 20-bit HDLC-type Pre-activation Proprietary Standard Based G.994.1 (g.hs) Rate Adaption Yes Yes Power Back-off No Yes Repeaters No Yes Timing Synchronous Synchronous + Plesiochronous pref. Synchronous Span Power Yes Yes
Connected Home Division Physical Layer How is the SHDSL PHY defined? Physical Layer Definition
Trellis Encoder Spectral/ Data Tomlinson Data Scrambler Convolusional Symbol Noise In Precoder Out Encoder Mapper Shaper
Echo Canceller
Data Viterbi Tomlinson Linear Data Descrambler + Out Decoder Modulo Equalizer In
Connected Home Division 23 Trellis Encoder – Adds redundancy PHY-TX: Trellis Encoder – Output depends on state and input (512 states) – Increases SNR – 3/4 bits in – 16/32-level PAM pulse out
Y0 Input X0 Convolutional from Encoder Y1 Frame One Serial to Mapper Dimensional S Parallel . . . d-2 d-1 d-0 Symbol Conversion X1 Mapper Payload Data Y2 (serial stream) X2 Y3
Level S: x*1/16 Mapper: Bit-to-level mapping -15 -13 -11 -9 -7 -5 -3 -1 1 3 5 7 9 11 13 15 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 Y3 Trellis 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 Y2 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 Y1 Encoder 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Y0 Output
Connected Home Division PHY-TX: Convolutional Encoder
Principle of a convolutional encoder
Y1
X1 T0 T1 T2 Shift Register
Y0
Block Diagram of a simple convolutional encoder
A sequence of bits enters the encoder at the input X1. After one delay the actual bit proceeds from T0 to T1, the first memory stage. After each delay the bits are forwarded to the next stage. Y1 is the result of an XOR multiplication of T0 and T2 and Y0 respectively of T0 and T1.
Connected Home Division PHY-TX: Tomlinson-Harashima Precoder
Tomlinson Precoder The idea of precoding is to move the + cancellation of the post-cursor ISI + Modulo to the transmitter where the past - transmitted symbols are known exactly. So the post-cursor impulse response must be known precisely at the Feedback transmitter. Filter
Tomlinson Precoder – Removes Inter-Symbol Interference (Decision - Feedback Equalizer function) – Modulo-n Filter – Results in expanded symbol set
Connected Home Division PHY-TX: Spectral Shaper • Frequency domain • PSD mask is independent of number of PAM-levels • PSD mask only depends on symbol rate Spectral Shaper • Total transmit power constant over the data rate • The PAM signal has infinite bandwidth –30
and cannot be sent by a real –40 transmitter. –50 256 kBit/s • The shaper performs the filtering on –60 512 kBit/s
the symbol sequence needed to (dBm/Hz) –70 768 kBit/s PSD produce a continuous-time signal for –80 1536 kBit/s transmission over the channel. –90 2048 kBit/s 2312 kBit/s –100
–110 0 0.2 0.4 0.6 0.8 1 T1541430-00 Frequency (MHz) (114701)
Connected Home Division S(H)DSL PSD Definition • Frequency domain • PSD mask is independent of number of PAM-levels • PSD mask only depends on symbol rate • Total transmit power constant over the data rate
–30
–40
–50
–60 256 kBit/s 512 kBit/s
(dBm/Hz) –70 768 kBit/s PSD –80 1536 kBit/s
–90 2048 kBit/s 2312 kBit/s –100
–110 0 0.2 0.4 0.6 0.8 1 T1541430-00 Frequency (MHz) (114701)
Connected Home Division PHY-RX: Echo Cancellation
Typical Echo Impulse Response: • Very long • High dynamic range on long loops (60+dB) • 200+ taps • Effects of bridged taps visible and important • Required due to full-duplex, spectrum overlapping baseband signaling • Requires loop-timing
Connected Home Division 30 PHY-RX: Equalizer
Equalizer Function for an SHDSL Transceiver • Training: DFEQ, converge, transform into THP • Showtime: THP@TX + LEQ@RX • Options: FSEQ, T-Spaced EQ • Enhancements: • Noise-Whitening/Prediction • Viterbi-Equalizer
Connected Home Division 31 PHY-RX: Viterbi Decoder
Viterbi Decoder uses the Viterbi algorithm, it is used not only to decode convolutional codes but also to produce the maximum-likelihood estimate of the transmitted sequence through a channel with inter-symbol interference (ISI). receives a sequence of bits and attempts to find a path in the trellis diagram with an output digit sequence that mostly agrees with the received sequence.
Connected Home Division 2/16-Level PAM at Receveiver @ baud rate
Connected Home Division Clocking / Loop Timing SHDSL Loop-Timing & Clocking Modes
Connected Home Division Framing Data Structure Block Diagram
48 bits per 6 ms 20 bits EOC Channel HDLC_E
per 6 ms OH Frame OH
SW Task SHDSL Data
48 blocks per 6 ms
DIN / PCLK PCM FIFO TFSC
48 * 125 us = 6 ms
PL BlocksPL Framer SHDSL
HW Block
Connected Home Division SDSL and SHDSL Frame Format (1)
Frame Structure ETSI-SDSL frame structure consistent with ITU G.shdsl frame structure
48*(1+i+n*8) bits 14 bit sync word Payload 14 2 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 2 [bits] 20 bit embedded eoc channel S P P P P P P P P P P p Sync O O O O 0 0 0 ...... 1 1 ...... 2 2 ...... 3 3 ...... 4 a word H H H H 1 2 3 2 3 4 5 6 7 8 r 6 bit crc e
4 fixed indicator bits 6 ms 0 ms 6 ms
Payload Sub-Block Symbol Name/Function i n * 8 [bits] P01 to P48 Payload blocks Z1 Z2 Z3 ... Zi B1 B2 B3 B4 ...... Bn OH SDSL overhead (eoc, crc,...) Sync word Double Barker code Spare Spare bits i=0,1,2,...7 n=3,4,5.....36 B B-channel (64 kbit/s), n = 3,4,5...,36 Z Z-bits i = 0,1,2,....,7 i = 0: no Z-bits
Connected Home Division SDSL and SHDSL Frame Format (2)
SDSL frame for synchronous transmission
14 2 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 2 [bits]
S P P P P P P P P P P p Sync O O O O 0 0 0 ...... 1 1 ...... 2 2 ...... 3 3 ...... 4 a word H H H H 1 2 3 2 3 4 5 6 7 8 r e
6 ms 0 ms 6 ms SDSL frame for plesiochronous transmission
14 2 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 10 12 * (i+n*8) 2 2 [bits]
S S P P P P P P P P P P t t Sync O O O O 0 0 0 ...... 1 1 ...... 2 2 ...... 3 3 ...... 4 u u word H H H H 1 2 3 2 3 4 5 6 7 8 f f f f
6 ms 0 ms 6 ms Connected Home Division EOC Message Frame Structure (HDLC)
Performance FOM: FLAG - 0x7E FLAG - 0x7E • SNR FLAG - 0x7E FLAG (optional) • Loop Attenuation FLAG (optional) Massage Segment: • BER •Identification Field •Standard Information Field • Sync-Status •Non-Standard Information Field FCS (first octet) Inventory FCS (second octet) FLAG - 0x7E • Unit-ID FLAG - 0x7E FLAG (optional) • Vendor
Connected Home Division Link Activation / Training Activation / Link-Training
Connected Home Division 42 G.944.1 Parameter Exchange
Training Parameters Stuff Bits
Max., Min. Brutto, Netto Data Rates Regenerators Max., Avg. Latency ATM, STM, HDLC/PTM … Framing Parameters Vendor ID
Sync. Word Line Probe Clock, Timing Modes Power Back Off (PBO) Sym., Asym. PSD Non Standard Information ...
Connected Home Division G.994.1
Central Office 12 kHz 20 kHz f
Remote End f 12 kHz 20 kHz
Parameters: STU-R TONES FLAG Msg1 Msg3 Msg4 Msg6 GALF STU-R • DPSK Modulation • 800 Bits Per Second • Frequency Division Multiplex • Time Division Multiplex (Half Duplex) STU-C TONES Msg2 Msg5 Msgx STU-C
Start-Up Transaction Clear-Down
Connected Home Division 44 Startup (G.991.2) LineProbing
.half duplex
.total duration ≤ tp-total =10s .low number of probes (typ. 2..10) .idle phases fix 200ms (±10ms) .no full transceiver training (no hybrid, timing section, echo canceller etc. due to short probes .Exact timing is listed in G.991.2, Chapter 6 .PMMS Probe timing depends on prior G.hs parameter exchange .PMMS related restrictions apply
Connected Home Division Startup (G.991.2) Core Activation (Training)
STU-R: PLL lock SHDSL Framer Sync
5s 1s
STU-C Sc Tc Fc Datac
STU-R Cr Sr Tr Datar
0,5s
1s 1,5s Cr, Sc, Sr: 2-PAM (2 level scrambled ones) „Scrambled ones“ Tc, Tr: 2-PAM (2 level data) activation frames 15s Fc: Activation frame with reversed sync word Datac,r: TC-PAM (multi level) data transmission Framesync: Transmission of payload data
Connected Home Division STU-C STU-R
T T Pair 0 ~ 20dB / Pair 0 Reference trace (2wire only) R ~3km PE0.4 R
T T Pair 1 Pair 1 R R ~ 20dB / ~3km PE0.4
Connected Home Division Noise Models and Channels/Cables FSAN Noise Model
FSAN Noise Model
• FSAN = BT, France Telecom, KPN, DTAG, NT LT Telia, Telecom Italia, Swisscom, Korea Telecom RX TX pair i • Developed by operators NEXT • New Noise model for SDSL and xDSL TX pair j RX FEXT performance tests pair k • Combined noise of different scenarios in TX Multipair distribution cable RX multipair cable
Connected Home Division FSAN Noise Models
Model A Model B (High Penetration Scenario) (Medium Penetration Scenario) . 90 SDSL . 15 SDSL . 90 ISDN/2B1Q . 10 ISDN/2B1Q . 40 HDSL/2B1Q (2-pair) . 4 HDSL/2B1Q (2-pair) . 90 ADSL over POTS . 10 ADSL-lite . 90 ADSL over ISDN . 5 ADSL over ISDN
Connected Home Division FSAN Noise Models
Model C (Legacy Scenario) Model D (Referece Scenario) . 15 SDSL . 49 SDSL . 10 ISDN/2B1Q . 4 HDSL/2B1Q (2-pair) . 10 ADSL-lite . 5 ADSL over ISDN . 4 ISDN-PRI/HDB3
Connected Home Division FSAN Noise Models
FSAN Model A: High Penetration Scenario -70 ETSI HDSL Increased Noise ADSL ETSI HDSL Standard Noise -80 ADSL HDSL SDSL -90
ISDN LT-Side
-100
dBm/Hz
-110
NT-Side
-120
FSAN Model A
-130 104 105 106 f/Hz Connected Home Division FSAN Noise Models
FSAN Model B: Medium Penetration Scenario
-80 ADSL -85 ADSL -90 HDSL SDSL -95 ISDN -100
-105
dBm/Hz LT-Side SDSL 2048 kbit/s -110 SDSL 384 kbit/s -115
-120 NT-Side -125 FSAN Model B -130 104 105 106 f/Hz
Connected Home Division FSAN Noise Models
FSAN Model C: Legacy Scenario-80
-85
-90 LT-Side -95
-100
-105
dBm/Hz NT-Side -110
-115
-120
-125 FSAN Model C -130 104 105 106 f/Hz
Connected Home Division FSAN Noise Models
FSAN Model D: 49 SDSL Disturbers
-80 2048 kbit/s -85 (asymmetric, downstream) 2048 kbit/s -90 (asymmetric, upstream)
-95 2048 kbit/s -100 (symmetric)
-105
dBm/Hz -110
-115 384 kbit/s (symmetric) -120
-125 FSAN Model D -130 104 105 106 f/Hz
Connected Home Division Other Impairments
• Bridged Taps • Wet Cables • RFI • Nonlinearities (Transformers) • Correlated Noise (Viterbi Performance)
Connected Home Division Rate vs. REACH Performance 32/64-PAM Extended Rates Noise-Free at PE04
32PAM 64PAM
Connected Home Division 58 16/32-PAM Extended Rates FSAN-B at PE04
16PAM 32PAM
Connected Home Division 59 16/32-PAM Ext. Rates FSAN-D (49Self) at PE04
32PAM 16PAM
ADC limit
Connected Home Division 60 S(H)DSL Applications Remote Power-Feeding
Connected Home Division 62 Multi-Hop “Daisy-Chain” with various RPF schemes
Extreme Long Reach MII/RMII MII/RMII Different cables n Repeater Different cables UTOPIA SHDSL 2 Transceiver SHDSL UTOPIA Bonding bk2bk Bonding TDM TDM
SHDSL SHDSL SHDSL SHDSL
SHDSL SHDSL SHDSL SHDSL
Connected Home Division 63 Node Node Node Loop Topologies with SHDSL with SHDSL with SHDSL
data data data Node Node data Ring (line with redundancy) data with SHDSL with SHDSL data data data
Node Node Node Point to Multipoint (star) 1. Node with SHDSL with SHDSL with SHDSL with SHDSL PHY
Node 2. Node with with SHDSL n SHDSL PHY
ports ...
n. Node with SHDSL Line PHY Node Node Node Node with SHDSL with SHDSL with SHDSL with SHDSL
data data data data
Connected Home Division 64 S(H)DSL Applications
Broadband services in new locations
Phone-booth WiFi Hotel and Emerging market Small cells Campus network Hot-Spot internet café business access
Energy – Military - Disaster
Oil platforms Disaster pre-warning Mining comms Military and rescue Fire control and seismology networks equipment networks
Infotainment, surveillance, ticketing and SOS
Infotainment Surveillance camera Public emergency Ticketing Info and advisement SOS systems screens
Connected Home Division 65 Discussion Further exploration (1)
Link Activation • Currently Link-Activation is about 30sec including G.hs. • With increased baud rates and reduced loop-length (1km only) the training times can be significantly reduced (at least 10x shorter, i.e. ~1sec) Autonegotiation • G.handshake (G.994.1) is essentially the same principle as Autoneg. For 1km of loop length it shall be verified what (trainingless) modulation scheme would serve the purpose to exchange capabilities and resolve onto a common mode. Line-Probing • Line-Probing can be omitted since the data-rate is fixed.
Connected Home Division 67 Further exploration (2)
Transformer • Currently the XFRM (EP7 footprint) is defined by the low data-rates. • Increasing and fixing baud-rates simplifies XFRM design and reduce cost Line-Code (PAM modulation depth) • Depending on noise-model, disturbance impairments and cable insertion loss the modulation scheme must be defined. Less PAM levels simplify EMI ingress disturbance handling but lift up the baud rate Error Coding • Currently only an inner code is defined. Parallel Bits are unprotected. Consider and outer code. Potentially Re-Tx.
Connected Home Division 68 Further exploration (3)
Fast Retrain (EEE) • A time budget of 100ms should be feasible considering that for 1000baseT the retrain is defined to be 200us at 125Mbaud vs. 100ms at 2.5MBaud. This looks yields a 10x margin considering filter lengths and convergence being similar (which it practically is in the same order of magnitude) • The basic refresh technology could be comparable to 1000baseT-EEE for a feasibility assessment. Transmit Signal • In a self-NEXT limited system the transmit power does not play a major role. It’s more about the alien NEXT disturbance. A reduction by 10x seems feasible considering no competing traditional telco-disturbers are in the same bundle.
Connected Home Division 69